There are known sensor-carrier caps made of plastic material, comprising a bottom wall which has a seat for accommodating the sensor and a lateral cylindrical interface wall for mounting the cap in a wheel hub assembly. The cap is mounted in the wheel hub assembly by interference between the interface wall and an outer ring of the wheel hub assembly. The lateral mounting wall is usually provided with a reinforcement made of metallic material which stiffens the wall. See, for example, US 2006/159377 A1. In some applications, the metal reinforcement is positioned on the radially outer surface of the cylindrical wall; in other cases, the reinforcement is embedded in the plastic material of the lateral wall. This reinforcement of metallic material not only increases the production cost of the sensor-carrier caps described above, but may also cause bimetallic problems when placed in contact with the outer ring of the wheel hub assembly.